FREEPORT, Maine — U.S. Sen.-elect Angus King said Wednesday a decision is coming soon on which party he’ll caucus with when he arrives in the U.S. Senate in January, but the independent former governor warned that his membership in a party caucus isn’t an automatic vote for that party and against the other.

“Some kind of caucus decision will be necessary,” he said at a news conference. “Once that decision is made, it doesn’t mean I’ll be locked into one side and the opponent of the other side. I want to continue to build bridges.”

King spoke in Freeport the morning after winning the race for Maine’s open U.S. Senate seat with a majority of the vote, besting his Republican and Democratic rivals, Secretary of State Charlie Summers and state Sen. Cynthia Dill. With 97 percent of precincts reporting, King had won 53 percent of the vote, compared with 31 percent for Summers and 13 percent for Dill.

King said he received congratulatory calls from and intends to meet this week with retiring U.S. Sen. Olympia Snowe and Sen. Susan Collins, who will be Maine’s senior senator.

He said he also received a congratulatory call from Nevada Sen. Harry Reid, the Democratic majority leader. King said he hasn’t yet heard from national Republican leaders or Maine Gov. Paul LePage.

Reid urged King to contact Sens. Bernie Sanders of Vermont and Joe Lieberman of Connecticut, two independents who caucus with Democrats, before he makes up his mind on caucusing with a party. Whichever decision King makes, however, it won’t decide which party controls the chamber. According to unofficial results, Senate Democrats had 54 seats to Republicans’ 45 following Tuesday’s votes.

King will travel to Washington, D.C., this weekend for an orientation as a new member of Congress. One of his first steps, he said, will be to reach out to fellow former governors in the Senate, including Jeanne Shaheen of New Hampshire, Mark Warner and Tim Kaine of Virginia, Tom Carper of Delaware and Lamar Alexander of Tennessee.

“Former governors tend to be more bipartisan,” he said. “They also tend to be action-oriented.”

And King said he’s holding out hope that senators can start to overcome the gridlock that’s characterized the chamber in recent years.

“There’s a general realization that if we’re going to solve the public’s problems, we’ve got to get over this idea of party,” he said.

King’s remarks followed a hard-fought race punctuated by an influx of nearly $7.4 million that poured into Maine’s Senate race from outside groups hoping to sway the election.

King and his challengers Tuesday night all discussed the influence of outside spending. Republican-leaning groups poured in a majority of the funds, $4.24 million, in an effort to peel away support from King and create an opening for Summers.

The Republican’s campaign “didn’t have the resources to counteract” that advertising, Summers said.

Despite the outside advertising, Summers said his campaign stuck to its original game plan.

“I’m very proud of the campaign,” he said. “I wouldn’t change a thing. I think we worked incredibly hard and really were able to take a campaign that nobody paid any attention to, to something that really became a hotly contested race.”

“When I look at the polls, they’re the same from beginning to end,” Dill said Tuesday night before voting at Cape Elizabeth High School. “At the end of the day, I don’t think it’s money that makes or breaks a campaign.”

While Maine’s 2012 Senate race was expensive and hotly contested, spending by the candidates for Maine’s open U.S. Senate seat fell well short of candidate spending in Maine’s last Senate race, in 2008.

That year, when U.S. Sen. Susan Collins was facing a challenge from former Democratic U.S. Rep. Tom Allen, candidate spending totaled $14.3 million.

Four years later, the candidates to replace Olympia Snowe had spent $5.3 million through mid-October.